Project description:Fluoroquinolone antibiotics, a common antibiotic for the treatment of Pseudomonas aeruginosa infection, are facing challenges due to the rapid evolution of bacterial resistance. Through designed evolutionary experiments in vitro, we find that there are significant differences in evolutionary trajectories and outcomes of resistant bacteria obtained in different induction modes, among which fitness benefit of resistant strains obtained in high-dose induction mode under high level of antibiotic is significantly higher than that of wild-type strain, and collateral sensitivity to aminoglycosides and some other antibiotics will be obtained. Resistance strains obtained in the low-dose induction mode exhibit higher heterogeneity, which is accompanied by multiple drug resistance (MDR). Through second generation resequencing and proteomic techniques, overexpression of MexCD-OprJ efflux pump induced by mutations in the nfxB gene significantly improved the fitness benefit of Pseudomonas aeruginosa PAO1 under high level of fluoroquinolones. This is the precondition of the further evolution of the fleroxacin-resistant strains in the high dose induction mode, the addition of the efflux pump inhibitor phenylalanyl arginyl β-naphthylamide (PAβN) could effectively repress the evolution of bacterial resistance in the high dose induction mode. Fleroxacin use followed by gentamicin helped drive infectious P.aeruginosa to extinction, causing nfxB mutation to cause collateral sensitivity to gentamicin.
Project description:There is an urgent need for novel antibiotics against carbapenem and 3rd generation cephalosporin-resistant Gram-negative pathogens, for which the last-resort antibiotics have lost most of their efficacy. We describe here a novel class of synthetic antibiotics that was inspired from natural product-derived scaffolds. The antibiotics have an unprecedented mechanism of action, which targets the main component (BamA) of the Bam folding machinery required for folding and insertion of ß-barrel proteins into the outer membrane of Gram-negative bacteria. This OMPTA (outer membrane protein-targeting antibiotic) class shows potent activity against multidrug-resistant Gram-negative ESKAPE pathogens and overcomes colistin-resistance both in vitro and in vivo. A clinical candidate has the potential to address life threatening Gram-negative infections with high unmet medical need.